code: def setup_class(cls):
      endog = mm.m_marietta
      exog = add_constant(mm.CRSP)
      mod = TLinearModel(endog, exog)
      res = mod.fit(method="bfgs", disp=False)
      modf = TLinearModel.from_formula(
          "price ~ CRSP", data={"price": mm.m_marietta, "CRSP": mm.CRSP}
      )
      resf = modf.fit(method="bfgs", disp=False)
      from .results_tmodel import res_t_dfest as res2
  
      cls.res2 = res2
      cls.res1 = res  # take from module scope temporarily
      cls.resf = resf
      cls.k_extra = 2
  
file_path: statsmodels/statsmodels/miscmodels/tests/test_tmodel.py
imports: import pytest
  import numpy
  from numpy.testing import assert_allclose
  from statsmodels.tools.tools import add_constant
  from statsmodels.tools.testing import Holder
  from statsmodels.miscmodels.tmodel import TLinearModel
label_desc: Use image node_id 1 for calling the TestTModel obj's underlying member method code with example usage: obj.setup_class(cls) without return types